Senior Aerothermal & CFD Engineer

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we’re building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage, where you’ll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.

We are seeking a Senior Aerothermal & CFD Engineer to develop computational fluid dynamics (CFD) and aerothermal solutions for Castelion’s long-range hypersonic strike vehicles. This role is critical to predicting aerodynamic loads, pressure distributions, and thermal environments that drive vehicle design. You will work hands-on with multidisciplinary engineering teams to analyze, model, and validate complex fluid dynamic and aerothermal phenomena from concept through flight test in a fast-paced, hardware-driven environment.

• Perform computational fluid dynamics (CFD) analyses of hypersonic flight vehicles across a wide range of Mach numbers and flight conditions
• Predict aerodynamic loads, pressure distributions, and surface heating environments for flight vehicle structures and thermal protection system
• Analyze shock interactions, boundary layer behavior, flow separation, and high-temperature flow phenomena
• Develop high-fidelity CFD models to support propulsion integration, control surface design, thermal protection systems, and vehicle configuration trades
• Work closely with flight sciences, TPS, structures, propulsion, GNC, and manufacturing teams to ensure seamless integration of aerodynamic and thermal analyses
• Correlate CFD predictions with wind tunnel, arc-jet, ground test, and flight test data to improve model fidelity
• Develop efficient meshing strategies, solver methodologies, and automated CFD workflows
• Support design reviews by providing aerodynamic and aerothermal analyses that inform key technical decisions
• Mentor junior engineers and contribute to best practices in CFD and aerothermal analysis
• Partner closely with program leadership to make technical trades aligned with mission success

• Bachelor’s, Master’s, or PhD in Aerospace Engineering, Mechanical Engineering, or related field
• 5+ years of experience performing CFD and aerothermal analysis for aerospace or defense applications
• Strong background in compressible fluid dynamics, hypersonic aerodynamics, and heat transfer
• Experience using CFD tools such as STAR-CCM+, Fluent, FUN3D, CFD++, US3D, or equivalent
• Experience with turbulence modeling, shock-boundary layer interactions, and high-temperature flow physics
• Familiarity with aerothermal heating prediction and thermal protection system design support
• Experience generating aerodynamic load and heating environments for structural and thermal analyses
• Experience with scripting and automation using Python, MATLAB, or equivalent
• Familiarity with wind tunnel testing, arc-jet testing, or flight test correlation
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high flight cadence environment

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

This position may require access to classified…